<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div class="container">
        <div class="left">
            111
        </div>
        <div class="main">
            222
        </div>
        <div class="right">
            333
        </div>
    </div>
    
    <style>
        .container{
            display: flex;
            justify-content: space-between; /* 根据需要调整间距 */  
        }
        .left .right .main{
            width:300px;
            height: 400px;
            border: 10px red solid;
            float:left;
            background-color: aqua;
            display: flex;
        }

    </style>
</body>
</html>